In a mobile vehicle communications system, a modem is used to establish a telephony data connection from a call center to a telematics unit. The modem dials the telephone number and waits for a response, also known as a “handshake,” to be sent from the telematics unit. If the wireless network is busy or is unavailable, the network sends a “network busy/customer unavailable” voice message within a few seconds. Current modems do not readily recognize the failure to establish the call, and have a typical timeout duration of sixty seconds or more.
Current network communications systems incorporating one or more outbound modems face several disadvantages. Such disadvantages often incur time delays in making connections due to one or more modems in the system being unavailable for an unacceptable length of time. In addition, typical systems depend upon an elaborate outbound re-try strategy in the event that a first connection attempt fails. Such re-try strategies often involve complex rules requiring unnecessary expenditures of time and functionality, usually to the disadvantage of overall system resources.
The present invention overcomes these disadvantages and advances the state of the art in mobile vehicle communication systems.